Linear-response resistance system for exercise equipment

ABSTRACT

A system for adjusting the resistance sensed by a user of a piece of exercise equipment. A pivotally mounted arm has at least one resistance magnet mounted thereto, and an adjustment actuator varies the proximity of the at least one resistance magnet to a resistance member of the piece of exercise equipment. The system provides a substantially linear relationship between the positional adjustment of the adjustment actuator and the resistance sensed by the user.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/635,509, filed Dec. 13, 2004, which application is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

The present invention relates generally to exercise equipment, and more particularly to a system for adjusting the resistance of a stationary bicycle or other type of exercise equipment, which provides a more linear relationship between the position of the knob or other adjustment actuator and the resistance sensed by the user.

BACKGROUND OF THE INVENTION

Various types of exercise equipment, such as for example stationary bicycles, provide resistance mechanisms for resisting activation by a user. For example, friction and magnetic resistance systems are known for providing dynamic resistance to the pedalling motion of a user of a stationary bicycle.

Because different users of a piece of exercise equipment may need differing levels of resistance, it is known to provide resistance mechanisms that are adjustable to increase or decrease the resistance to user activation. For example, a good athlete may require a high level of resistance to provide a good workout, enabling the user to generate pedalling power on the order of 400 watts; whereas a less fit user may need a lower level of resistance, pedalling at around seventy watts. Such resistance mechanisms are commonly adjusted by manual operation of an adjustment knob or other manual adjuster, or by operation of electronic controls.

A fundamental advantage of magnetic resistance systems for exercise equipment, as compared to friction systems, is that they are very quiet. However, previously known magnetic resistance systems typically suffer from the disadvantage that the power required to turn the pedals (the resistance felt by the user) does not increase proportionally with the position of the adjustment knob, because the magnetic field strength varies in an inverse cubic relationship to distance from the magnet field. Adjustment of many prior magnetic resistance systems results in a generally linear variation in the magnet spacing of the resistance mechanism, which typically does not result in linear variation in resistance, but rather a variation wherein sequential settings at low resistance levels are very close together, but sequential settings at high resistance levels generate very large changes in resistance.

Thus it can be seen that needs exist for improvements to resistance systems for exercise equipment, which provide a more linear relationship between adjustor setting or position and resistance. It is to the provision of an improved resistance system meeting these and other needs that the present invention is primarily directed.

SUMMARY OF THE INVENTION

In example forms, the present invention is an improved resistance system for exercise equipment such as a stationary bicycle, treadmill, stair-climber, etc. having a magnetic resistance system, which provides a more linear relationship between adjustor setting and resistance.

In one aspect, the present invention is a resistance system for exercise equipment, having resistance magnets mounted on a pivotally mounted lever arm, for varying the proximity of the magnets to the resistance wheel, and thereby providing a more linear relationship between adjustor position and resistance. An intermediate linkage is pivotally mounted to the lever arm, and carries the adjustment cable, such that toggling of the intermediate linkage adjusts the proximity of the resistance magnets to the resistance member in a non-linear manner that provides a substantially linear variation in the resistance sensed by the user. The adjustor can be, for example, a manual knob, an electronic controller, or other adjustment actuation mechanism.

In another aspect, the present invention is a system for adjusting the resistance sensed by a user of a piece of exercise equipment. The system allows a user to adjust the resistance of the piece of exercise equipment in such a manner as to provide a substantially linear relationship between each adjustment and the resistance sensed by the user. The system has a pivotally mounted arm with at least one resistance magnet mounted thereto, and an adjustment actuator for varying the proximity of the at least one resistance magnet to a resistance member of the piece of exercise equipment. The system varies the proximity of the at least one resistance magnet to the resistance member of the exercise equipment such that an adjustment by the adjustment actuator and the resistance sensed by the user of such equipment has a substantially linear relationship.

In another aspect, the present invention is an exercise apparatus having at least one energy input mechanism for activation by a user, and a resistance system for varying a user-perceived degree of resistance to activation of the at least one energy input mechanism. The resistance system comprises an actuation mechanism having a plurality of resistance settings. Each of the resistance settings correspond to one of a plurality of resistance levels. Furthermore, the user-perceived degree of resistance to activation of the at least one energy input mechanism varies in substantially equal increments between each sequential resistance setting of the actuation mechanism.

In still other aspect, the present invention is a method of varying the resistance to user activation of an exercise apparatus. The method comprises generating substantially equal variation in a level of resistance generated by the exercise apparatus between each of a plurality of sequential resistance settings.

In a further aspect of the method described above, the exercise apparatus of the present invention has a resistance system with first and second magnetically-attracted members separated a distance from one another. The level of resistance generated by the magnetic resistance system varies relative to the distance of separation between the first and second magnetically-attracted members according to a first non-linear relationship. This aspect of the present invention also includes generating variation of the distance of separation between the first and second magnetically-attracted members between sequential resistance settings according to a second non-linear relationship that is substantially inverse to the first non-linear relationship.

These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a magnetic resistance system according to an example embodiment of the invention.

FIG. 2 shows a user operating a piece of exercise equipment of the type to which the present invention is applicable.

FIG. 3 shows manual adjustment of a resistance mechanism.

FIG. 4 shows an electronic adjuster for a resistance system according to the present invention.

FIG. 5 shows a detailed view of a portion of the magnetic resistance system of FIG. 1, in a low-resistance setting.

FIG. 6 shows another detailed view of a portion of the magnetic resistance system of FIG. 1, in a medium-resistance setting.

FIG. 7 shows another detailed view of a portion of the magnetic resistance system of FIG. 1, in a high-resistance setting.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.

Referring to the drawing figures, FIG. 1 shows a linear-response magnetic system 10 according to an example embodiment of the present invention. The magnetic system 10 of the present invention may be used in conjunction with multiple types of exercise equipment that have a need for linear adjustable resistance, such as a stationary exercise bicycle 12 as shown in FIG. 2, or other forms of exercise equipment such as a treadmill, stair-climber, cross-country ski machine, or other forms of resistance training mechanisms. The bicycle 12 preferably includes seat, handlebars, pedals, display and resistance adjustment mechanism, mounted to a frame or body. The present invention enables a user to increase or decrease the resistance felt while pedaling the exercise bicycle 12 in a linear fashion (i.e., in substantially equal increments of perceived resistance loading between sequential settings through substantially the entire range of adjustment), such that each sequential increase or decrease in resistance setting on the bicycle produces a substantially equal increase or decrease in actual resistance force at the pedals.

Returning now to FIG. 1 and FIGS. 5-7, a magnetic resistance system according to an example embodiment of the present invention is thereby shown, comprising an annular flywheel 20, at least one magnet 30 in proximity to the flywheel, a spring biased plate 40 carrying the at least one magnet, a resistance-adjustment actuation mechanism such as an electric motor 50, a pivotal carrier arm 60, and a fixed frame 70.

In the depicted embodiment, the flywheel 20 is belt or chain driven by the user's action of pedaling pedals or other input mechanism(s) of the bicycle 12 and is provided with a rotatable axis of revolution 22. The axis of revolution 22 may include any mechanism by which the flywheel 20 is permitted to rotate thereon, including but not limited to, a bearing, an axle, and/or a bolt and nut configuration. In preferred embodiments, the flywheel 20 is permanently or adjustably connected to the frame 70 of the exercise bicycle 12, although in alternate embodiments the flywheel is independent of the frame or directly coupled to a bicycle's pedal assembly. In exemplary embodiments the flywheel 20 is constructed of iron, steel, or other material(s) having a high degree of magnetic permeability (i.e. magnetic attraction). In other embodiments, the flywheel 20 is made of polymers, ceramics, lead, or other materials having a low degree of magnetic permeability, and coated with a material having a high degree of magnetic permeability, such that at least the external circumferential face 22 of the flywheel is sensitive or reactive to magnetic fields. Regardless of the material(s) used to construct the flywheel 20, it is preferable that the flywheel be equally weighted about its circumference to provide for smooth and quiet interaction with a user pedaling the stationary bicycle 12.

An elongated spring biased plate 40 is preferably hingedly mounted to the frame 70 at a first end thereof, such that as the plate pivots, its inner face is in variable proximity to at least a portion of the flywheel's 20 circumference. The plate 40 is preferably radiused to have a semicircular profile, generally matching the radius of curvature of the flywheel 20. The spring biased plate 40 has at least one, and more preferably a plurality of permanent magnets 30 extending longitudinally from one end of the plate to the other, a pivotal axis 42 secured to the frame 70, and a spring 44 to bias the plate from the flywheel 20 in opposition to the adjustment force applied by the adjustment actuator. In other embodiments, the plate 40 comprises a single permanent magnet and/or at least one electromagnet. The axis of rotation 42 may be a bearing, hinge, axle, and/or a bolt and nut configuration, or any other means by which the plate 40 is permitted to rotate thereabout. A limit screw or member extending from the plate 40 preferably abuts against the frame to prevent contact between the magnets 30 and the flywheel 20.

Rather than using frictional resistance as with traditional exercise equipment, the magnets 30 of the present invention provide dynamic resistance to motion of the flywheel 20 through application of a magnetic field to the flywheel. This allows the exercise bicycle 12 to operate with fewer mechanical parts, no frictional wear, requires less maintenance by the user, and is quieter than traditional friction-resistance exercise equipment. As the magnets 30 move further away from the flywheel 20, the resistance felt by a user turning the flywheel is decreased, and as the magnets move closer to the flywheel, the resistance is increased. The relationship between the strength of the magnetic field exerted on the external face 22 of the flywheel 20 and the distance the magnets are positioned from the flywheel is not linear. Rather, the strength of the magnetic field exerted on the flywheel 20 by the magnets 30 is related to the distance the magnets are spaced from the flywheel by an inverse cubic relationship. For example, if the spacing between the magnets 30 and the flywheel 20 is doubled, the magnetic field exerted on the flywheel roughly decreases by a factor of eight. Therefore, in order for a user to feel a linear change in resistance at the pedals 20 (i.e., equal increments of increase or decrease in perceived resistance force) per each incremental change in the resistance setting on the bicycle 12, each incremental change in resistance setting must result in sequentially increasing degrees of rotation of the spring biased plate 40 as the resistance setting is reduced, and sequentially decreasing degree of rotation of the plate 40 as the resistance setting is increased, in order to compensate for the nonlinear relationship between resistance and the distance from the magnetic field to the flywheel 20. In other words, the plate 40 moves a greater distance between the lowest and second-lowest resistance settings than between the second-lowest and third-lowest setting; a greater distance between the second and third lowest setting than between the third and fourth-lowest settings, and so forth. In an example embodiment, the distance of spacing between the magnets 30 and the magnetically-attracted surface of the flywheel 20 varies between sequential resistance settings through the range of adjustment according to a non-linear relationship that is substantially inverse to the inverse cubic relationship of magnetic field strength to spacing distance.

In example embodiments, the rotational movement of the spring biased plate 40, and therefore the proximity of the magnets 30 to the external face 22 of the flywheel 20, is accomplished by advancement and retraction of at least one bowden wire or cable 80 coupled at one end to the actuation mechanism and at the other end to the pivotal carrier arm 60, and a second wire or cable coupled between the arm 60 and the plate 40. In other embodiments, the bowden wire 80 may be fixed to the carrier arm 60 and have its ends connected to the activation mechanism and the spring biased plate 40. In example embodiments, the actuation mechanism is an electric motor 50. The motor 50 is preferably controlled by a controller 90 (FIG. 4) to retract or release a predetermined length of the bowden wire 80 depending on the amount of rotational movement required of the spring biased plate 40 to meet the resistance needs of the user. The sheath of the bowden wire 80 is preferably connected to the frame 70 through a connecting arm bearing 72. In alternate example embodiments, the actuation mechanism is a manually controlled knob 150 as shown in FIG. 3. In still further embodiments, the actuation mechanism is directly coupled to the spring biased plate 40 without having the bowden wire 80 interact with a pivotal carrier arm 60.

A proximal end of the pivotal carrier arm 60 is preferably connected to the frame 70 at a pivot axis 62 as depicted in FIGS. 5-7. The pivot axis can comprise a bearing, axle, and/or a bolt-and-nut connection. In preferred embodiments, the carrier arm 60 has a first slot 64, to which an end of the bowden wire 80 is fastened at a distal end of the arm 60. A second piece of linkage wire or chain 82 is fastened to a second slot 66 in the distal end of the carrier arm 60, linking the carrier arm with the spring biased plate 40. The pivotal carrier arm 60 can be made of any of a variety of materials including, but not limited to, plastics, ceramics, metals, and/or metal alloys.

In operation, a user interacting with a piece of exercise equipment incorporating the linear-response magnetic system 10 of the present invention, such as an exercise bicycle 12 as depicted in FIG. 2, can increase or decrease the, resistance felt while pedaling the bicycle. In example embodiments of the present invention, a user can initiate such a change in resistance through a digital controller and output display device 90 as shown in FIG. 4. The controller 90 preferably comprises input means 92 for increasing and/or decreasing the resistance settings and/or a display screen 94 denoting the current resistance setting. The input means 92 preferably comprises, buttons, dial(s), a touchscreen, or other means by which a user can electronically adjust the resistance settings. In alternative example embodiments, a user initiates a change in resistance through the use of a manually controlled knob 150 as seen in FIG. 3. In such alternative embodiments, the knob 150 can incorporate a display 152 to identify the current resistance setting to a user.

FIG. 5 shows the resistance mechanism at its lowest resistance setting, wherein the spring biased plate 40 and magnets 30 carried thereon are at their farthest position (i.e., greatest spacing) from the flywheel 20. In this setting, the resistance felt by a user is a minimum. To increase the resistance, the plate 40 is moved closer to the flywheel 20, such that the magnetic attraction between the plate and the flywheel increases. A user incrementally increases the resistance provided by operating the actuation mechanism to move the plate 40 closer to the flywheel 20 by operation of the controller 90, the manual knob 150, or other form of actuator, for example to retract the bowden wire 80. As the wire 80 retracts, the distal end of the pivotal carrier arm 60 is rotated towards the connecting arm bearing 72, thereby wrapping the second piece of linkage wire or chain 82 around the external surface 68 of the carrier arm. As the linkage wire 82 wraps around the carrier arm 60, the spring biased plate 40 pivots towards the flywheel 20, thereby decreasing the magnetic spacing and increasing the resistance a user feels at the pedals when operating the exercise bicycle. In order to incrementally increase the resistance linearly in accordance with sequential increases in resistance settings on the controller 90, the spring biased plate 40 pivots towards the flywheel 20 at a decreasing rate with each increasing setting position, as explained above. Because the effective radius of the pivotal carrier arm 60 varies as it rotates (in a similar fashion to that of an eccentric cam), equal increments of retraction or release of the bowden wire 80 generate greater or lesser increments of motion of the second linkage wire 82 (and accordingly greater or lesser degree of motion of the plate 40 and magnets 30 carried thereon), depending on the angular position of the pivotal carrier arm. Therefore, by appropriate positioning and sizing of the pivotal carrier arm 60, linear increments of resistance setting input can generate the desired non-linear increments of magnetic spacing output, and thereby provide substantially equal (linear) changes in perceived resistance between sequential resistance settings through the range of resistance adjustment.

In example embodiments, the desired non-linear adjustment of magnetic spacing is generated by controlling the output of the resistance system using a pivotal carrier arm as described above. In alternate embodiments, the desired non-linear adjustment of magnetic spacing is generated by controlling the actuation mechanism. For example, the controller 90 can be programmed to vary the number of revolutions of the motor 50 between resistance settings, to increase the degree of retraction or release of the bowden wire 80 at lower resistance settings, and decrease the retraction or release distance at higher resistance settings. In manually-controlled embodiments, sequential settings of the adjustment knob or other actuation mechanism can be configured to vary the rate of bowden cable retraction and release between resistance settings in similar fashion. In still further embodiments, non-linear adjustment of magnetic spacing is generated by a combination of both the provision of a pivotal carrier arm and control of the rate of retraction or release of bowden wire between resistance settings.

FIG. 6 shows the resistance mechanism 10 of the present invention in a medium resistance setting, and FIG. 7 depicts the system 10 in a maximum resistance setting. In order to incrementally lower the resistance felt by a user as a user sequentially lowers the resistance settings, the actuation mechanism releases a predetermined length of bowden wire 80 and the plate 40 pivots away from the flywheel under the bias of the spring 44 to increase the magnetic spacing. In alternate embodiments, a user retracts or releases a predetermined length of bowden wire 80 between sequential settings by actuation of the electronic controller 90 and motor 50, or by actuation of the manual control knob 150. In still further embodiments, the actuation mechanism, whether in the form of motor 50 or manual control knob 150, may be directly connected to the spring biased plate 40 through a piece of linkage wire or chain, thereby eliminating the need for the pivotal carrier arm 60.

While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims. For example, while the invention has been described as a resistance mechanism for a bicycle, other embodiments take the form of a magnetic resistance mechanism providing linear incremental adjustment of user-perceived resistance force for other forms of exercise equipment such as a treadmill, a stair-climber, a cross-country ski machine, or other form of resistance training mechanism. In such embodiments, the user inputs motion in various forms other than pedaling, as will be understood by persons of ordinary skill in the art, and non-linear control of magnetic resistance spacing is carried out in similar fashion to that described above, to generate linear increments of resistance change between sequential resistance settings. 

1. A system for adjusting the resistance sensed by a user of a piece of exercise equipment, said system comprising: a magnetically permeable resistance member and at least one magnet separated by a magnetic distance; an adjustment actuator having a plurality of resistance settings comprising at least a high-resistance setting, a medium-resistance setting, and a low-resistance setting; and means for changing the magnetic distance a greater amount upon shifting the adjustment actuator between the low-resistance setting and the medium-resistance setting, and changing the magnetic distance a lesser amount upon shifting the adjustment actuator between the medium-resistance setting and the high-resistance setting.
 2. The system of claim 1, wherein the means for changing the magnetic distance comprises a pivotal carrier arm and at least one cable coupled to said pivotal carrier arm.
 3. The system of claim 1, wherein the means for changing the magnetic distance comprises a motor and a controller for generating a greater number of revolutions of said motor upon shifting the adjustment actuator between the low-resistance setting and the medium-resistance setting, and a lesser number of revolutions of said motor upon shifting the adjustment actuator between the medium-resistance setting and the high-resistance setting.
 4. The system of claim 1, wherein the adjustment actuator and the means for changing the magnetic distance comprise a manual knob having indexed positions corresponding to the high-resistance setting, the medium-resistance setting, and the low-resistance setting.
 5. The system of claim 1, wherein the magnetically permeable resistance member comprises a flywheel having at least an outer surface with a high degree of magnetic permeability.
 6. The system of claim 1, wherein the at least one magnet is carried on a pivotally mounted arm.
 7. The system of claim 6, wherein the at least one magnet comprises a plurality of permanent magnets positioned along the pivotally mounted arm.
 8. An exercise apparatus comprising at least one energy input mechanism for activation by a user, and a resistance system for varying a user-perceived degree of resistance to activation of the at least one energy input mechanism, the resistance system comprising an actuation mechanism having a plurality of resistance settings, each of said plurality of resistance settings corresponding to one of a plurality of resistance levels, and wherein the user-perceived degree of resistance to activation of the at least one energy input mechanism varies in substantially equal increments between each sequential resistance setting of the actuation mechanism.
 9. The exercise apparatus of claim 8, wherein said resistance system further comprises at least one magnet and at least one magnetically attracted member, and wherein the at least one magnet moves relative to the at least one magnetically attracted member in response to a change in the resistance setting of the actuation mechanism.
 10. The exercise apparatus of claim 9, wherein a spacing between the at least one magnet and the at least one magnetically attracted member varies non-linearly between sequential resistance settings of the actuation mechanism.
 11. The exercise apparatus of claim 8, wherein said actuation mechanism comprises a controller for varying a number of rotations of a motor generated by a change between each sequential resistance setting.
 12. The exercise apparatus of claim 8, wherein said actuation mechanism is coupled to a variable intermediate linkage for non-linearly varying an output of said resistance system.
 13. The exercise apparatus of claim 11, wherein the variable intermediate linkage comprises a pivotal carrier arm coupled to a cable.
 14. The exercise apparatus of claim 8, wherein said actuation mechanism is coupled to a variable intermediate linkage for non-linearly varying an output of said resistance system in response to a change of resistance settings, and means for applying a non-linear variation to an input to the variable intermediate linkage between each sequential resistance setting.
 15. The exercise apparatus of claim 14, wherein said means for applying a non-linear variation to the input comprises a motor controller for varying a number of rotations of a motor in response to a change between each sequential resistance setting.
 16. The exercise apparatus of claim 14, wherein said means for applying a non-linear variation to the input comprises a manual adjustor having non-linear spacing between each sequential resistance setting.
 17. A method of varying resistance to user activation of an exercise apparatus, said method comprising generating a substantially equal variation in a level of resistance generated by said exercise apparatus between each of a plurality of sequential resistance settings.
 18. The method of claim 17, wherein the exercise apparatus comprises a magnetic resistance system having first and second magnetically-attracted members separated a distance from one another, and wherein the level of resistance generated by the magnetic resistance system varies relative to the distance of separation between the first and second magnetically-attracted members according to a first non-linear relationship, said method comprising generating variation of the distance of separation between the first and second magnetically-attracted members between sequential resistance settings according to a second non-linear relationship that is substantially inverse to the first non-linear relationship.
 19. The method of claim 17, wherein the substantially equal variation in the level of resistance generated by said exercise apparatus between each of the plurality of sequential resistance settings is generated by non-linear variation of an input to a resistance-adjustment mechanism.
 20. The method of claim 19, wherein the non-linear variation of the input to the resistance-adjustment mechanism comprises actuation of a motor to generate a varying number of motor revolutions upon shifting the apparatus between each sequential resistance setting.
 21. The method of claim 20, wherein the non-linear variation of the input to the resistance-adjustment mechanism comprises actuation of a manual adjustor having non-linear spacing between each sequential resistance setting.
 22. The method of claim 17, wherein the substantially equal variation in the level of resistance generated by said exercise apparatus between each of the plurality of sequential resistance settings is generated by non-linear variation of an output of a resistance-adjustment mechanism.
 23. The method of claim 22, wherein the non-linear variation of the output of the resistance-adjustment mechanism is generated by actuation of a variable intermediate linkage portion of the resistance-adjustment mechanism.
 24. The method of claim 23, wherein the variable intermediate linkage portion of the resistance-adjustment mechanism comprises a pivotal carrier arm coupled to a bowden cable. 